title: Effects of 12-month exercise on health-related quality of life: a randomized controlled trial.
abstract: OBJECTIVE
  We investigated exercise effects on health-related quality of life (HRQOL) and exercise self-efficacy, and tested effect modification by baseline body mass index (BMI) and gender.
  
  
  METHODS
  Middle-aged women (n=100) and men (n=102) were randomly assigned to either exercise (360 min/week of moderate-to-vigorous aerobic exercise) or control in Seattle, WA, from 2001 to 2004. Demographics, anthropometrics, exercise self-efficacy (5-item self-efficacy questionnaire) and HRQOL (SF-36) were assessed at baseline and 12 months. Analysis of covariance adjusting for baseline scores was used to compare HRQOL and exercise self-efficacy scores between the exercise and control groups.
  
  
  RESULTS
  At 12 months, exercisers demonstrated higher exercise self-efficacy than controls (percent change from baseline: -6.5% vs. -15.0%, p < 0.01), without differences in HRQOL. Baseline BMI category and gender did not modify these effects. In exploratory analyses comparing exercisers and controls within subgroups defined by gender and BMI, 12-month HRQOL scores [role-physical (+7.0% vs. -13.1%), vitality (+15.6% vs. -4.2%), social functioning (+10.0% vs. -3.5%), and mental health (+6.8% vs. -2.9%)] were higher only among overweight male exercisers (p < 0.05, vs. control).
  
  
  CONCLUSIONS
  Three hundred and sixty minutes per week of exercise, recommended for weight maintenance, did not have negative effects on exercise self-efficacy or HRQOL. This level of exercise may increase HRQOL among overweight men.
authors.affiliation: Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA. iimayama@fhcrc.org
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Imayama
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Alfano
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Cadmus Bertram
authors.forename: Chiachi
authors.initials: C
authors.lastname: Wang
authors.forename: Liren
authors.initials: L
authors.lastname: Xiao
authors.forename: Catherine
authors.initials: C
authors.lastname: Duggan
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Campbell
authors.forename: Karen E
authors.initials: KE
authors.lastname: Foster-Schubert
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015444:Exercise / Q000523:psychology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D011795:Surveys and Questionnaires; D014861:Washington